1. Field of the Invention
The present invention relates to a sheet post-processing apparatus and a sheet post-processing method that perform post-processing for a sheet discharged from an image forming apparatus such as a copier, a printer, or a composite device.
2. Description of the Related Art
In recent years, there is developed a sheet post-processing apparatus which is disposed adjacent to the sheet discharge section of an image forming apparatus main body for the purpose of performing post-processing, such as sorting and stapling, for a sheet on which an image has been formed in the image forming apparatus. For example, in a post-processing apparatus that performs stapling processing, a plurality of sheets (sheet bundle) are aligned by an alignment means and stapled and, after that, fed to a sheet discharge tray to sequentially be loaded thereonto.
Such a sheet post-processing apparatus performs post-processing for a succeeding sheet after completion of the post-processing for a preceding sheet. Although the stapled sheet bundle is discharged onto the sheet discharge tray, the sheet alignment performance may deteriorate or the sheet may be folded at the time of discharge in some cases depending on the size, quality, stiffness or thickness of the sheet to be processed.
Jpn. Pat. Appln. Laid-open Publication No. 2004-155551 discloses a sheet discharge apparatus. The sheet discharge apparatus in this disclosure is featured in the configuration of a sheet discharge table, in which ingenuity has been applied thereto to prevent the discharged sheets from being disturbed. However, this disclosure does not cope with the deterioration of the sheet alignment performance due to a difference in the sheet type.
An object of the present invention is to provide a sheet post-processing apparatus and a sheet-post processing method capable of preventing the sheets discharged onto a sheet discharge tray from being disturbed to thereby enhancing the sheet alignment performance.